Pacific Science Center

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PacSci-Doku: “Sun’s Energy”

By Dennis Schatz – Senior Advisor

Do you Sudoku? It’s one of the hottest number games around! Well, here’s a twist we think you’ll love. We call it PacSci-Doku. Can you guess why? Here’s how it works. Instead of filling in the blanks with numbers, we use letters. Hidden in one of the columns or rows is the answer to a science question. You’ll find information about the answer on the answer tab below.

The question in this edition is:

What is the energy source of the Sun?

To find the answer, complete this PacSci-Doku using the following nine letters:

U  Y  O  N  E  G  R  D  H

PacSci-Doku: "Sun's Energy"

Puzzle Difficulty: Hard

The Answer

PacSci-Doku: "Sun's Energy" AnswerThe question in this edition is:

What is the energy source of the Sun?

The answer: Hydrogen

The center of the Sun is so hot and under so much pressure that hydrogen atoms are fusing together to form helium atoms. This releases vast amounts of energy that keeps the Sun hot and produces the outward pressure needed to keep the Sun from collapsing under its own gravitational force. In 4.5 billion years the Sun will run out of hydrogen in its core. When that happens, the center of the Sun will collapse and get hotter until it can fuse helium into carbon. At the same time, the Sun’s outer layers will expand and cool until the Sun’s surface is beyond the orbit of the Earth. The Sun will then be a red giant star, much like the star Betelguese in the constellation of Orion. Read more about the fusion reaction powering the Sun.

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